title: Fast fat-suppressed reduced field-of-view temperature mapping using 2DRF excitation pulses.
abstract: The purpose of this study is to develop a fast and accurate temperature mapping method capable of both fat suppression and reduced field-of-view (rFOV) imaging, using a two-dimensional spatially-selective RF (2DRF) pulse. Temperature measurement errors caused by fat signals were assessed, through simulations. An 11×1140μs echo-planar 2DRF pulse was developed and incorporated into a gradient-echo sequence. Temperature measurements were obtained during focused ultrasound (FUS) heating of a fat-water phantom. Experiments both with and without the use of a 2DRF pulse were performed at 3T, and the accuracy of the resulting temperature measurements were compared over a range of TE values. Significant inconsistencies in terms of measured temperature values were observed when using a regular slice-selective RF excitation pulse. In contrast, the proposed 2DRF excitation pulse suppressed fat signals by more than 90%, allowing good temperature consistency regardless of TE settings. Temporal resolution was also improved, from 12 frames per minute (fpm) with the regular pulse to 28 frames per minute with the rFOV excitation. This technique appears promising toward the MR monitoring of temperature in moving adipose organs, during thermal therapies.
authors.affiliation: Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong. jyuan@cuhk.edu.hk
authors.forename: Jing
authors.initials: J
authors.lastname: Yuan
authors.forename: Chang-Sheng
authors.initials: CS
authors.lastname: Mei
authors.forename: Bruno
authors.initials: B
authors.lastname: Madore
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: McDannold
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Panych
mesh_terms: D001831:Body Temperature; D001834:Body Water; D002611:Cheese; D017352:Echo-Planar Imaging / Q000379:methods*; D005223:Fats; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D014464:Ultrasonic Therapy
chemical_list: D005223:Fats